In exercising a delegated power the President or another officer may effectively suspend or rescind a law passed by Congress, or may preempt state law. A rule or regulation properly promulgated under authority received from Congress is law, and under the supremacy clause of the Constitution can preempt state law.135 Similarly, a valid regulation can supersede a federal statute. Early cases sustained contingency legislation giving the President power, upon the finding of certain facts, to revive or suspend a law,136 and the President’s power to raise or lower tariff rates equipped him to alter statutory law.137 The Court in Opp Cotton Mills v. Administrator138 upheld Congress’s decision to delegate to the Wage and Hour Administrator of the Labor Department the authority to establish a minimum wage in particular industries greater than the statutory minimum but no higher than a prescribed figure. Congress has not often expressly addressed the issue of repeals or supersessions, but in authorizing the Supreme Court to promulgate rules of civil and criminal procedure and of evidence it directed that such rules supersede previously enacted statutes with which they conflict.139